A flexible tape heater (110) in a patient conduit (112) may be used to heat the flow of gas in the patient conduit (112) that is delivered to the patient mask (116). The thin, flat and extended nature of the flexible tape heater (110) may enhance heat transfer with the gas flow while also providing low impedance to the gas flow. Heating of the gas may facilitate the desired temperature and humidity to be reached for the gas delivered to the patient by the respiratory apparatus. The flexible tape heater (110) may be placed in the patient conduit (112) such that the flexible tape heater (110) is twisted or bent about one or more of the flexible tape heater's (110) three axes. Additionally these configurations may be used to enhance the turbulent mixing of the water vapor produced in the humidification chamber (114) with the gas flow.